1. Field of the Invention
2. Related Background Art
Trainer cups comprising a container for liquid with a lid including a mouthpiece, usually in the form of a spout, are well known for use at an intermediate stage in a child's development as it moves from drinking from a feeding bottle or the breast to drinking from a conventional cup or glass.
However, at that stage, the child will not have learned that if cups are knocked over or shaken, the liquid inside will be spilt. Accordingly, there is a need for the development of trainer cups which are adapted not to spill their contents when shaken or upturned.
United Kingdom Patent Specification GB 2 266 045 A describes such a cup in which a one-way valve is provided within the spout of the lid of a trainer cup.
The valve is formed by a slit formed in an externally convex portion of a sheet of flexible material such as latex or silicone rubber. The valve opens in response to suction on the spout by the child, thereby allowing egress of fluid from the cup. The convexity of the valve provides the one-way characteristic of the valve. A second one-way valve is provided to allow ingress of air into the cup, to prevent the build up of a vacuum.
However, at some stage in a child's development, it will need to learn the skills involved in drinking from the rim of an ordinary cup. Typically this is done by wholly removing the lid from the trainer cup. However, in doing so, the spill-resistance advantages are completely lost. The object of the present invention is to provide an improved drinking vessel which can be used as a trainer cup.